1. Field of the Invention
The present invention relates to a data processing apparatus in which pieces of coded picture data generated in a data terminal equipment such as a personal computer are decoded, converted in size and decoded to produce pieces of line data, and the line data are transmitted to another personal computer or a facsimile equipment through a communication line generally utilized.
2. Description of the Related Art
A so-called modem equipment is generally utilized to execute data communication between personal computers. That is, the modem equipment is utilized to connect an interface of the personal computer with a telephone line. Wherein, the interface is manufactured according to an interface standard RS-232C.
Recently, a so-called facsimile adapter or a so-called facsimile modern equipment has been developed to execute data communication between a facsimile equipment and the personal computer or between facsimile equipments. That is, the facsimile adapter or the facsimile modem equipment is manufactured by adding a transmission function between the facsimile equipments to the modem equipment.
2.1. PREVIOUSLY PROPOSED ART
A conventional facsimile adapter is described with reference to FIGS. 1 to 4.
FIG. 1 is a block diagram schematically showing the configuration of a conventional data processing system.
As shown in FIG. 1, a conventional data processing system 11 is provided with a data terminal equipment 12 such as a personal computer, and a data circuit-terminating equipment 13 such as a conventional facsimile adapter. The data terminal equipment 12 is connected with the data circuit-terminating equipment 13 through a local line 14 such as a RS-232 interface. The data circuit-terminating equipment 13 is connected with a communication line 15 generally utilized. Therefore, pieces of digital data generated in the data terminal equipment 13 are, for example, transmitted to transform the digital data to analog signals in the data circuit-terminating equipment 13, and the analog signals are transmitted to a data terminal equipment of the other party through the communication line 15 to execute facsimile communication. Wherein, the facsimile communication is executed according to T. 30 of the International Consultative Committee for Telephone and Telegraph (CCITT).
In cases where pieces of data generated in the data terminal equipment 13 are transmitted to the general communication line 15 through the data circuit-terminating equipment 13, the pieces of data are transmitted to the local line 14, and the data are temporarily stored in a first buffer 16 of the data terminal equipment 13. Thereafter, the data stored in the first buffer 16 are processed in a data processing section 17 of the data circuit-terminating equipment 13 as necessary, and the data are transferred to a second buffer 18. Thereafter, the data stored in the second buffer 18 are modulated in a transmit-receive modem 19, and the modulated data are transmitted to another personal computer or another facsimile equipment of the other party through the general communication line 15. This transmitting operation is controlled by a control section (not shown).
In cases where pieces of data generated in the other party are received in the data terminal equipment 12, the data transmitting the general communication line 15 are received by the transmit-receive modem 19, and the data are temporarily stored in the second buffer 18. Thereafter, the data stored in the second buffer 18 are processed in the data processing section 17 as necessary, and the data are transferred to the first buffer 16. Thereafter, the data stored in the first buffer 16 are received in the data terminal equipment 12 through the local line 14. This receiving operation is controlled by the control section.
The operation of the data circuit-terminating equipment 13 is executed according to either a facsimile mode or a data communication mode. For example, picture information which is compressed and coded is transmitted between the data terminal equipment 12 and the facsimile equipment of the other party according to the facsimile communication mode. Also, coded information is transmitted between the data terminal equipment 12 and the personal computer of the other party according to the data communication mode.
In case of the facsimile communication mode, there are two types off operation of the data circuit-terminating equipment 13. One type of the operation is that the picture information compressed and coded is transmitted to the general communication line 15 without processing the picture information in the data processing section 17. Another type of the operation is that the picture information compressed and coded is transmitted to the general communication line 15 after the picture information is processed in the data processing section 17. For example, in cases where pieces of modified READ (MR) coded data can be received by the facsimile equipment off the other party and in cases where pieces of modified Hussmann (MH) coded data are transmitted from the data terminal equipment 12 to the general communication line 15, the pieces of MH coded data generated in the data terminal equipment 12 are converted into pieces of MR coded data in the data processing section 17 to shorten communication time required to transmit the MH coded data to the facsimile equipment of the other party, and the MR coded data are transmitted to the general communication line 15. This operation is called a code conversion processing. Also, in cases where only a B5 size of recording papers are prepared for the facsimile equipment of the other party and in cases where pieces of picture data formatted to an A4 size of recording papers are transmitted from the data terminal equipment 12 to the general communication line 15, the size of the picture data generated in the data terminal equipment 12 are converted in the data processing section 17 before the picture data are transmitted to the general communication line 15. This operation is called a size conversion processing. In addition, a large number of pieces of picture data generated in the data terminal equipment 12 are generally managed in lines. In short, a piece of line data formed of pieces of picture data is produced for each line of a sheet of manuscript which is read by a facsimile equipment. Therefore, in cases where the number of pieces of picture data contained in a piece of line data is lower than a predetermined minimum number MIN, the pieces of picture data are zerofilled to increase the number of pieces of picture data to the predetermined minimum number MIN. That is, a series of digits "0" is added to the line data. Thereafter, the picture data zerofilled are transmitted to the general communication line 15. This operation is called a zerofill addition processing.
Next, those operations executed in the data circuit-terminating equipment 13 are concretely described.
Pieces of compressed/coded picture data generated in the data terminal equipment 12 are serially transmitted to the data circuit-terminating equipment 18 through the local line 14, and the picture data are stored in the first buffer 16, for example, in bytes. The compressed/coded picture data are managed in the second buffer 16 in pieces of line data. Each of pieces of line data are added a specific code EOL which denotes the end of a line and is arranged at the end of the line data in the first buffer 16. In this case, the byte number of a piece of line data is not constant. Also, the code conversion processing, the size conversion processing and the zerofill addition processing are executed for each piece of line data in the data processing section 17. That is, the specific code EOL of each piece of line data stored in the first buffer 16 is searched by the data processing section 17 to check whether or not the line data is stored in the first buffer 16 (this operation is called an EOL search processing). Thereafter, in cases where the specific code EOL is found out according to the EOL search processing, the line data found out is took out from the first buffer 16, and the line data took out is transferred to the data processing section 17. This operation is called a line data taking out processing executed by a data taking out section (not shown).
The data processing section 16 and the data taking out section are generally made by a micro processor. And, the operations executed in the data processing section 16 such as the code conversion processing, the size conversion processing, the zerofill addition processing, and the EOL search processing and the line data taking out processing executed in the data taking out section are programmed in the micro processor. Therefore, those processings are executed in software.
In case of the data communication mode, a dynamic adaptation type of data compressing method and a data extending method are adopted. That is, information formed of character codes generated in the data terminal equipment 12 is compressed in the data circuit-terminating equipment 13 according to the data compressing method, and the information compressed are transmitted to the general communication line 15. Also, information formed of character codes received from the general communication line 15 is extended in the data circuit-terminating equipment 13 according to the data extending method. As a result, the amount of the information transmitted to the general communication line 15 is lessened so that the communication between the parties is efficiently executed.